I think more than likely ezy would drop the routes from belfast,
They couldn't really compete with the frequency EIR could offer
As well as that if would people the option of travelling with one airline and back with a other if it made the trio cheaper
Can't really do that at the moment as you would be going to a different airport
Many a time I flew to Bhx with flybe but back on bmibaby and vice versa as it worked out cheaper